[Third_Time_Lucky]

I'm thinking a connector got a bit wet & an erroneous signal (or lack of one) was interpreted as high temperature?

Re the steam, I guess it was just bits (radiator, exhaust manifold etc) also getting wet & drying out quickly ... however I think I'd be looking at coolant levels carefully fr the next few days in case they've blasted a hole in the rad (or a bit of rust that was holding the coolant in)...